Find the missing permutation: Difference between revisions
→{{header|Picat}}
(→{{header|Wren}}: Now uses Wren-perm module.) |
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print_r(array_diff($finalres,$givenPerms)); // Array ( [20] => DBAC )
</lang>
=={{header|Picat}}==
Here are several approaching, including constraint modelling, with sets (ordset), and permutations.
<lang picat>import util.
import ordset.
import cp.
main => go.
go =>
P1 = ["ABCD","CABD","ACDB","DACB","BCDA","ACBD",
"ADCB","CDAB","DABC","BCAD","CADB","CDBA",
"CBAD","ABDC","ADBC","BDCA","DCBA","BACD",
"BADC","BDAC","CBDA","DBCA","DCAB"],
Perms = permutations("ABCD"),
% very imperative
Missing = _,
foreach(P in Perms, Missing = _)
Found = false,
foreach(T in P1)
if P == T then
Found := true
end
end,
if not Found then
Missing := P
end
end,
println(missing1=Missing),
% somewhat less imperative
Missing2 = _,
foreach(P in Perms, Missing2 = _)
if not member(P,P1) then
Missing2 := P
end
end,
println(missing2=Missing2),
% using findall (predicate)
println(missing3=difference(Perms,P1)),
% findall approach as a one-liner
println(missing4=findall(X,(member(X,Perms),not(member(X,P1))))),
% using ordsets
println(missing5=subtract(new_ordset(Perms),new_ordset(P1))),
% list comprehension (and member for the check)
println(missing6=[P:P in Perms,not member(P,P1)]),
% maps
Map = new_map(),
foreach(P in P1) Map.put(P,1) end,
println(missing7=[P: P in Perms, not Map.has_key(P)]),
% "merge sort" variant, using sorted lists
% (zip/2 requires that the length of the two lists are the same, hence the dummy)
PermsSorted = Perms.sort(),
P1Sorted = P1.sort(),
Found2 = false,
foreach({P,PP} in zip(PermsSorted,P1Sorted ++ ["DUMMY"]), Found2 = false)
if P != PP then
println(missing8=P),
Found2 := true
end
end,
% variant with list comprehension
A = [cond(P == PP,1,0) : {P,PP} in zip(PermsSorted,P1Sorted ++ ["DUMMY"])],
println(missing9=[PermsSorted[I] : I in 1..PermsSorted.length, A[I] = 0].first()),
% shorter
println(missing10=[P:{P,PP} in zip(PermsSorted,P1Sorted ++ ["DUMMY"]), P != PP].first()),
% CP variant
ABCD = new_map(['A'=1,'B'=2,'C'=3,'D'=4]),
% convert to integers (for the table constraint)
P1Table = [ [ABCD.get(C,0) : C in P].to_array() : P in P1],
Missing3 = new_list(4), Missing3 :: 1..4,
all_different(Missing3),
table_notin({Missing3[1],Missing3[2],Missing3[3],Missing3[4]},P1Table),
solve(Missing3),
ABCD2 = "ABCD",
println(missing11=[ABCD2[I] : I in Missing3]),
% matrix approach
PermsLen = Perms.length,
P1Len = P1.length,
A2 = new_array(PermsLen,P1Len), bind_vars(A2,0),
foreach(I in 1..PermsLen, J in 1..P1Len, Perms[I] = P1[J])
A2[I,J] := 1
end,
println(missing12=[Perms[I] : I in 1..PermsLen, sum([A2[I,J] : J in 1..P1Len])=0]),
% inspired by the Perl 6 xor variant
println(missing13=to_fstring("%X",reduce(^,[parse_term("0x"++P):P in P1]))),
% count the character with the least occurrence (=5) for each positions (1..4)
% (based on my K version)
println(missing14=[[O:O=5 in Occ]:Occ in [occurrences([P[I]:P in P1]):I in 1..4]]),
% variant using sorting the occurrences
println(missing15a=[C:C=_ in [sort2(Occ).first():Occ in [occurrences([P[I]:P in P1]):I in 1..4]]]),
% transpose instead of array index
println(missing15b=[C:C=_ in [sort2(O).first():T in transpose(P1),O=occurrences(T)]]),
% extract the values with first
println(missing15c=[sort2(O).first():T in transpose(P1),O=occurrences(T)].map(first)),
println(missing15d=[sort2(O).first().first():T in transpose(P1),O=occurrences(T)]),
println(missing15e=[S[1,1]:T in transpose(P1),S=sort2(occurrences(T))]),
% delete/2
Perms2 = Perms,
foreach(P in P1) Perms2 := delete(Perms2,P) end,
println(missing16=Perms2),
nl.
difference(Xs,Ys) = findall(X,(member(X,Xs),not(member(X,Ys)))).
% return a map with the elements and the number of occurrences
occurrences(List) = Map =>
Map = new_map(),
foreach(E in List)
Map.put(E, cond(Map.has_key(E),Map.get(E)+1,1))
end.
% sort a map according to values
sort2(Map) = [K=V:_=(K=V) in sort([V=(K=V): K=V in Map])]
</lang>
Output:
<pre>
missing1 = DBAC
missing2 = DBAC
missing3 = [DBAC]
missing4 = [DBAC]
missing5 = [DBAC]
missing6 = [DBAC]
missing7 = [DBAC]
missing8 = DBAC
missing9 = DBAC
missing10 = DBAC
missing11 = DBAC
missing12 = [DBAC]
missing13 = DBAC
missing14 = [D,B,A,C]
missing15a = DBAC
missing15b = DBAC
missing15c = DBAC
missing15d = DBAC
missing15e = DBAC
missing16 = [DBAC]
</pre>
=={{header|PicoLisp}}==
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